132 W 132 μJ Femtosecond Pulses from a Coherently Combined System of Two Rod-Type Photonic Crystal Fibers

• Published in: Photonics Vol. 10; no. 10; p. 1138
• Main Authors: Xie, Gehui, Luo, Daping, Tang, Zhenqiang, Deng, Zejiang, Zhou, Lian, Pan, Jiayi, Gu, Chenglin, Li, Can, Liu, Yang, Leng, Jinyong, Zhou, Pu, Li, Wenxue
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2023
• Subjects: Accumulation; Amplification; Amplifiers; coherent combining; Crystal fibers; Energy; Femtosecond pulses; fiber lasers and amplifiers; Fiber optics; Fibers; Frequency dependence; Integrals; Lasers; Optical components; Optics; Photonic crystals; Polarization; Pulse duration; ultrafast lasers
• ISSN: 2304-6732; 2304-6732
• DOI: 10.3390/photonics10101138

A coherent beam combination has the potential to revolutionize high-peak-power laser systems. However, achieving a high-average-power ultrashort pulse is difficult due to the accumulation of a nonlinear phase and gain narrowing. In this article, we demonstrate a coherent beam combination system that does not require pulse shaping or a spectral modulator. By optimizing the gain of each amplifier and using highly integrated optical components, we reduce the limitations caused by the accumulation of a nonlinear phase and gain narrowing. In our study, we used a polarization beam splitter to combine the pulses from two rod-type photonic crystal fibers (PCFs) in a Mach–Zehnder-type interferometer. A piezo-mounted mirror controlled with a Hänsch–Couillaud polarization detecting system was used to stabilize active phase locking. The system produces 165 W with a 91.6% combining efficiency compared to 90 W per amplifier. Compressed pulses with an energy of 132 µJ and Gaussian fitting pulse duration of 330 fs were achieved.